V-belt pulley

ABSTRACT

V-belt pulley comprising an outer rim ( 2 ) provided with at least one V-belt groove ( 7 ) formed by turning, said groove ( 7 ) having a bottom ( 9 ) provided with a plurality of radially through-going and circumferentially interspaced openings ( 8 ). The pulley is cast with a rim ( 2 ) having a radially inwardly facing surface ( 4 ) is provided with a plurality of circumferentially interspaced recesses ( 5 ) of such a radial depth that the radially through-going openings are formed by the turning thereof.

TECHNICAL FIELD

The invention relates to a V-belt pulley comprising an outer rimprovided with at least one outwardly facing V-belt groove formed byturning in whose bottom a plurality of radially through-going openingsare circumferentially interspaced and extend to the radially inwardlyfacing surface of the rim.

BACKGROUND ART

Such a V-belt pulley is known from GB patent nr. 865 797, in which theradial openings are formed by radial cutting through the rim of theV-belt pulley.

BRIEF DESCRIPTION OF THE INVENTION

The object of the invention is to provide a V-belt pulley of the abovetype which can be made in a simple and rational manner.

The V-belt pulley according to the invention is characterised in thatthe pulley is cast with a rim having a radially inwardly facing surfaceprovided with a plurality of circumferentially interspaced recesses ofsuch a radial depth that the bottom thereof is arranged radially outsideof the bottom of the V-belt groove such that the radially through-goingopenings are made by the turning thereof.

By forming the V-belt pulley with said recesses in its rim, the openingsare automatically produced by turning of the V-belt groove. The cuttingprocess of the V-belt pulley may thus be carried out in a mannercorresponding to a conventional V-belt pulley without radial openings,whereby separate machining thereof is avoided. Consequently V-beltpulleys with openings which act to cool the pulley and V-belt and thusprolongs the life of the latter can be made essentially withoutincreased production costs. Tests have shown that by using the V-beltpulley according to the invention the belt temperature is decreased by10-15° C. in relation to the use of conventional V-belt pulleys withoutradial openings in the bottom of the groove.

According to the invention, when seen in axial direction the radialrecesses may have a groove-like form and thus be cast without usingseparate cores.

Furthermore according to the invention the recesses may be axiallythrough-going from one side of the pulley to the other.

Moreover according to the invention the openings may be substantiallyevenly interspaced when seen in circumferential direction.

According to the invention, the radial openings may be of a lengthsubstantially corresponding to their interspacing when seen incircumferential direction.

Furthermore according to the invention the length of the openings may be7-30 mm, preferably 15-25 mm when seen in circumferential direction.

Moreover according to the invention the depth of the recesses is suchthat the radial outer portion of the openings made by the turning of thegroove is arranged radially inside of the V-belt received in the groove,whereby the V-belt does not engage the portion of the V-belt groove, inwhich the openings are formed.

Finally according to the invention the V-belt pulley may be made of SGiron.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in greater detail below with reference to theaccompanying drawing, in which

FIG. 1 is a side view of the V-belt pulley according to the inventionand

FIG. 2 illustrates the V-belt pulley in FIG. 1 along the line II—II inFIG. 1.

BEST MODE FOR CARRYING OUT THE INVENTION

The drawing illustrates a cast V-belt pulley according to the inventioncomprising a hub 1 connected to a rim 2 by means of three spokes 3.During casting a plurality of recesses 5 is formed in the radiallyinwardly facing surface 4 of the rim, said recesses 5 beingcircumferentially evenly interspaced between the spokes 3. In axialdirection the recesses 5 have a groove-like form and extend from oneside of the rim to the other. Four V-belt grooves 7 are formed in theouter surface of the rim by turning. The depth of the grooves 7 and therecesses 5 is such that openings 8 are formed between the bottom 9 ofthe grooves adjacent recesses when the grooves are turned. In otherwords, the bottom 13 of the recesses is arranged radially outside of thebottom 9 of the grooves 7. For illustration hereof the bottom 9 of thegrooves 7 is shown as a dotted line in FIG. 1 and in the enlargedsection thereof—even though it is not visible in these Figures.

As it appears from the far right groove in FIG. 2, the depth of therecesses 5 is further such that the radially outer portion 10 of theopenings formed by turning of the grooves is arranged radially inwardlyof a V-belt 11 (shown dotted) received in the groove, whereby the V-beltis prevented from coming into contact with the openings and thus frombeing damaged. The hub is provided with an axial conical bore formounting the V-belt pulley on a shaft.

As mentioned above the V-belt pulley is made by cutting of a castworkpiece. The cast workpiece may be formed by any casting process,i.e., by using a non-permanent (expendable) mould or a permanent mould.Furthermore the cast workpiece may be of any metal or iron alloy.However, preferably the cast workpiece is made of SG iron by sandcasting.

Preferably, the only surfaces of the V-belt pulley which are processedby machining are. The outer peripheral face 6 of the groove 7, thelateral faces 14, 15 and the bore 12 and the lateral faces 16,17 of thehub 1.

As a result of the obtained cooling action, the V-belt pulley accordingto the invention is particularly advantageous in connection with thevarious types of narrow V-belts, ie type SPA, SPZ, SPB and SPC, but canof course be adapted to other types of V-belts.

What is claimed is:
 1. A V-belt pulley which is cast with an outer rimhaving a radially inwardly facing surface and with a plurality of castrecesses circumferentially spaced along said inwardly facing surfacewith each recess having a depth which extends radially outwardly fromsaid inwardly facing surface; and at least one radially outwardly facingV-belt groove formed in said outer rim by turning, each said at leastone V-belt groove having a bottom which intersects said radiallyoutwardly extending recesses to form a plurality of circumferentiallyspaced openings extending from the respective V-belt groove to theinwardly facing surface of the outer rim.
 2. A V-belt pulley inaccordance with claim 1, wherein each recess is a groove which extendsgenerally parallel to an axial direction of said V-belt pulley.
 3. AV-belt pulley in accordance with claim 2, wherein each recess extendsfrom a first side of the pulley to a second side of the pulley.
 4. AV-belt pulley in accordance with claim 3, wherein said openings aresubstantially evenly spaced when viewed in circumferential direction ofsaid outer rim.
 5. A V-belt pulley in accordance with claim 4, whereineach opening has a length in the circumferential direction of said outerrim which substantially corresponds to spacing between the openings inthe circumferential direction of said outer rim.
 6. A V-belt pulley inaccordance with claim 5, wherein the depth of the recesses is such thata V-belt received in the respective V-belt groove would not enter theradially outer portions of the openings.
 7. A V-belt pulley inaccordance with claim 4, wherein the depth of the recesses is such thata V-belt received in the respective V-belt groove would not enter theradially outer portions of the openings.
 8. A V-belt pulley inaccordance with claim 3, wherein each opening has a length in thecircumferential direction of said outer rim which substantiallycorresponds to spacing between the openings in the circumferentialdirection of said outer rim.
 9. A V-belt pulley in accordance with claim8, wherein the depth of the recesses is such that a V-belt received inthe respective V-belt groove would not enter the radially outer portionsof the openings.
 10. A V-belt pulley in accordance with claim 3, whereinthe depth of the recesses is such that a V-belt received in therespective V-belt groove would not enter the radially outer portions ofthe openings.
 11. A V-belt pulley in accordance with claim 2, whereinsaid openings are substantially evenly spaced when viewed incircumferential direction of said outer rim.
 12. A V-belt pulley inaccordance with claim 11, wherein each opening has a length in thecircumferential direction of said outer rim which substantiallycorresponds to spacing between the openings in the circumferentialdirection of said outer rim.
 13. A V-belt pulley in accordance withclaim 12, wherein the depth of the recesses is such that a V-beltreceived in the respective V-belt groove would not enter the radiallyouter portions of the openings.
 14. A V-belt pulley in accordance withclaim 11, wherein the depth of the recesses is such that a V-beltreceived in the respective V-belt groove would not enter the radiallyouter portions of the openings.
 15. A V-belt pulley in accordance withclaim 2, wherein each opening has a length in the circumferentialdirection of said outer rim which substantially corresponds to spacingbetween the openings in the circumferential direction of said outer rim.16. A V-belt pulley in accordance with claim 15, wherein the depth. ofthe recesses is such that a V-belt received in the respective V-beltgroove would not enter the radially outer portions of the openings. 17.A V-belt pulley in accordance with claim 2, wherein the depth of therecesses is such that a V-belt received in the respective V-belt groovewould not enter the radially outer portions of the openings.
 18. AV-belt pulley in accordance with claim 1, wherein each recess extendsfrom a first side of the pulley to a second side of the pulley.
 19. AV-belt pulley in accordance with claim 18, wherein said openings aresubstantially evenly spaced when viewed in circumferential direction ofsaid outer rim.
 20. A V-belt pulley in accordance with claim 19, whereineach opening has a length in the circumferential direction of said outerrim which substantially corresponds to spacing between the openings inthe circumferential direction of said outer rim.
 21. A V-belt pulley inaccordance with claim 20, wherein the depth of the recesses is such thata V-belt received in the respective V-belt groove would not enter theradially outer portions of the openings.
 22. A V-belt pulley inaccordance with claim 19, wherein the depth of the recesses is such thata V-belt received in the respective V-belt groove would not enter theradially outer portions of the openings.
 23. A V-belt pulley inaccordance with claim 18, wherein each opening has a length in thecircumferential direction of said outer rim which substantiallycorresponds to spacing between the openings in the circumferentialdirection of said outer rim.
 24. A V-belt pulley in accordance withclaim 23, wherein the depth of the recesses is such that a V-beltreceived in the respective V-belt groove would not enter the radiallyouter portions of the openings.
 25. A V-belt pulley in accordance withclaim 18, wherein the depth of the recesses is such that a V-beltreceived in the respective V-belt groove would not enter the radiallyouter portions of the openings.
 26. A V-belt pulley in accordance withclaim 1, wherein said openings are substantially evenly spaced whenviewed in circumferential direction of said outer rim.
 27. A V-beltpulley in accordance with claim 26, wherein each opening has a length inthe circumferential direction of said outer rim which substantiallycorresponds to spacing between the openings in the circumferentialdirection of said outer rim.
 28. A V-belt pulley in accordance withclaim 27, wherein the depth of the recesses is such that a V-beltreceived in the respective V-belt groove would not enter the radiallyouter portions of the openings.
 29. A V-belt pulley in accordance withclaim 26, wherein the depth of the recesses is such that a V-beltreceived in the respective V-belt groove would not enter the radiallyouter portions of the openings.
 30. A V-belt pulley in accordance withclaim 1, wherein each opening has a length in the circumferentialdirection of said outer rim which substantially corresponds to spacingbetween the openings in the circumferential direction of said outer rim.31. A V-belt pulley in accordance with claim 30, wherein the depth ofthe recesses is such that a V-belt received in the respective V-beltgroove would not enter the radially outer portions of the openings. 32.A V-belt pulley in accordance with claim 1, wherein the depth of therecesses is such that a V-belt received in the respective V-belt groovewould not enter the radially outer portions of the openings.
 33. Amethod of forming a V-belt pulley which comprises the steps of: castinga pulley with an outer rim having a radially inwardly facing surface andwith a plurality of cast recesses circumferentially spaced along saidinwardly facing surface with each recess having a depth which extendsradially outwardly from said inwardly facing surface; and then machiningat least one radially outwardly facing V-belt groove in the outer rim ofthe thus cast pulley, with each said at least one V-belt groove having abottom which intersects said radially outwardly extending recesses toform a plurality of circumferentially spaced openings extending from therespective V-belt groove to the inwardly facing surface of the outerrim.
 34. A method in accordance with claim 33, wherein each recess is agroove which extends generally parallel to an axial direction of saidV-belt pulley.
 35. A method in accordance with claim 33, wherein eachrecess extends from a first side of the pulley to a second side of thepulley.
 36. A method in accordance with claim 33, wherein said openingsare substantially evenly spaced when viewed in circumferential directionof said outer rim.
 37. A method in accordance with claim 33, whereineach opening has a length in the circumferential direction of said outerrim which substantially corresponds to spacing between the openings inthe circumferential direction of said outer rim.
 38. A method inaccordance with claim 33, wherein the depth of the recesses is such thata V-belt received in the respective V-belt groove would not enter theradially outer portions of the openings.